1,720,970 research outputs found
Linear and non-linear parameterization of EEG during monitoring of carotid endarterectomy
No full textIn this paper, new quantitative linear (HLF ratio: high frequency/low frequency spectral power ratio) and non-linear parameters (ZC: zero crossing and FD: fractal dimension) which can assist the physician in real-time decision whether a shunt is required or not during intra-operative EEG monitoring of carotid endarterectomy are presented. The results obtained with the new parameters are compared with those achieved by other indexes proposed in the literature. The HLF ratio and ZC parameters yielded the best results with a 100% of correct identification of both shunt and no-shunt situations. The ZC can be also easily implemented in the real-time monitoring of EEG
A case of nocturnal frontal lobe epilepsy in a patient with spinocerebellar ataxia type 17.
No full textSystems of Acoustic Resonance at Ancient Sites and Related Brain Activity: Preliminary Results of Research
No full textResearch was carried out in collaboration with the Head and Neck Department and the Clinical Neurophysiological Unit at the University of Trieste (Italy) to assess the effects of resonance phenomena on the human body. We worked with volunteers who underwent examination by EEG while listening to tones between 90Hz and 120Hz, similar to the resonant sounds found at some Neolithic structures in Europe (England, Ireland, Italy, Malta). As in the study by Ian Cook at the University of California (UCLA, 2008), all of our volunteers were subjected to a "comfortable" volume of sound whilst in the absorbing sound room. This is used for audiometric tests at the Otorhinolaryngology Clinic and has been modified with suitable software and hardware. This type of room is also protected by a Faraday cage to shield from any possible external electromagnetic interference that could affect the results. After two minutes of silence to evaluate the resting brain rhythm, the volunteers were subjected to the tones of 90, 95, 100, 105, 110, 115, 120Hz arranged in a random way for one minute each. At the end of every cycle they listened to a mantra of the same frequency for a period of two minutes. Technicians examined the EEGs to verify the data collected. They found there was a prevalence of frontal areas or occipital (posterior) areas with no predominance of one cerebral hemisphere (left of right) over the other during playing. Each volunteer had a different sensitivity to all the tones without one tone prevailing (i.e. 110Hz), with each exhibiting a strong response to a subjective and personal tone (90Hz, 105Hz, 120Hz...)
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Linear and non-linear effects of gradient artifact filtering methods in simultaneous EEG-fMRI
No full textVariations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
EEG Analysis in Resting State and during a Memorization Task in Mild Cognitive Impairment and Subjective Cognitive Impairment
No full textMild Cognitive Impairment (MCI) and Subjective Cognitive Impairment (SCI) are brain disorders with a high risk to progress to Alzheimer’s disease. This work investigates the possible EEG differences in MCI and SMC subjects, with respect to control subjects (CS), both during rest and cognitive stimulation. EEG data were analyzed by decomposing the power spectral density into frequency sub-bands and by calculating the power-law beta exponent parameter. Moreover, from a nonlinear point of view, also Higuchi’s fractal dimension and Poincaré plot indexes were estimated. Feature extraction was performed by using the Principal Component Analysis method, in an effort to distinguish CS, MCI and SCI patients. Results show that some parameters present statistically significant differences between SCI and control subjects, whereas MCI patients present intermediate values between the other two groups. The use of the principal component analysis allows a preliminary visual separation of CS and SCI, even if the difficulty in distinguishing MCI subjects persists
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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